The cartilage under your kneecap is a natural shock absorber. Overuse, injury or other factors may lead to a condition known as chondromalacia patella (kon-droh-muh-LAY-shuh puh-TEL-uh) — a general term indicating damage to the cartilage under your kneecap. A more accurate term for chondromalacia patella is patellofemoral (puh-tel-o-FEM-uh-rul) pain syndrome.

The most common symptom is knee pain that increases when you walk up or down stairs. Simple treatments — such as rest and ice — often help, but sometimes physical therapy or even surgery is needed to ease patellofemoral pain.

Patellofemoral pain syndrome usually causes a dull, aching pain in the front of your knee. This pain can be aggravated when you:

Walk up or down stairs

Kneel or squat

Sit with a bent knee for long periods of time

When to see your doctor

If the knee pain doesn't improve within a few days, consult your doctor.

Patellofemoral pain can lead to difficulty with routine activities, such as squatting and climbing stairs.

You're likely to start by seeing your family doctor. In some cases, you may be referred to a physical therapist, an orthopedic surgeon or a sports medicine specialist.

What you can do

Before your appointment, you might want to write a list of answers for the following questions:

Have you ever injured your knee?

When did your symptoms start?

Have you had X-rays or other imaging exams of your knees in the past? (If so, try to arrange to bring copies of them with you to your appointment.)

What medications or supplements are you taking?

What to expect from your doctor

Your doctor may ask some of the following questions:

How would you describe your knee pain?

Where exactly does it hurt?

Does any particular activity make your symptoms better or worse?

Have you recently increased your level of athletic activity?

What home treatments have you tried already? Did they help?

During the physical exam, your doctor will press on different parts of your knee and move your leg into a variety of positions. These maneuvers will help rule out other conditions that have similar signs and symptoms.

To help determine the cause of your knee pain, your doctor may recommend imaging tests such as:

X-rays. A small amount of radiation passes through your body in the process of creating X-ray images. This technique visualizes bone well, but is less effective at viewing soft tissues.

Computerized tomography (CT) scan. CT scans combine X-ray images taken from many different angles to create cross-sectional images of internal structures. CT scans can visualize both bone and soft tissues, but the procedure delivers a much higher dose of radiation than do plain X-rays.

Magnetic resonance imaging (MRI). Using radio waves and a strong magnetic field, MRIs produce very detailed images of bones and soft tissues. But MRIs are much more expensive than X-rays or CT scans.

Treatment of patellofemoral pain often begins with simple measures. Rest your knee as much as possible. Avoid any activities that increase the pain, such as climbing stairs.

Medications

Therapy

A physical therapist may suggest:

Rehabilitation exercises. Specific exercises can strengthen the muscles that support your knees and control limb alignment, such as your quadriceps, hamstrings and the muscles around your hips (especially the hip abductors).

Supportive braces. Knee braces or arch supports may help protect your joint and improve the alignment of your kneecap.

Taping. Your physical therapist may show you how to tape your knee to reduce pain and enhance your ability to exercise.

Ice. Icing your knee after exercise may be especially helpful.

Knee-friendly sports. During your recovery, you may want to restrict your activities to sports that are easier on the knees — such as bicycling and swimming.

Surgical and other procedures

Arthroscopy. During this procedure, the doctor inserts an arthroscope — a pencil-thin device equipped with a camera lens and light — into your knee through a tiny incision. Surgical instruments are passed through the arthroscope to remove fragments of damaged cartilage.

Realignment. In more-severe cases, a surgeon may need to operate on your knee to realign the angle of the kneecap or relieve pressure on the cartilage.

Sometimes knee pain just happens. But certain steps may help prevent the pain.

Think alignment and technique. Ask your doctor or physical therapist about flexibility and strength exercises to optimize your technique for jumping, running and pivoting — and to help the patella track properly in its groove. Especially important is exercise for your outer hip muscles to prevent your knee from caving inward when you squat, land from a jump or step down from a step.

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